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  <div class="section" id="cmp0066">
<span id="policy:CMP0066"></span><h1>CMP0066<a class="headerlink" href="#cmp0066" title="Permalink to this headline">¶</a></h1>
<p>Honor per-config flags in <span class="target" id="index-0-command:try_compile"></span><a class="reference internal" href="../command/try_compile.html#command:try_compile" title="try_compile"><code class="xref cmake cmake-command docutils literal notranslate"><span class="pre">try_compile()</span></code></a> source-file signature.</p>
<p>The source file signature of the <span class="target" id="index-1-command:try_compile"></span><a class="reference internal" href="../command/try_compile.html#command:try_compile" title="try_compile"><code class="xref cmake cmake-command docutils literal notranslate"><span class="pre">try_compile()</span></code></a> command uses the value
of the <span class="target" id="index-0-variable:CMAKE_&lt;LANG&gt;_FLAGS"></span><a class="reference internal" href="../variable/CMAKE_LANG_FLAGS.html#variable:CMAKE_&lt;LANG&gt;_FLAGS" title="CMAKE_&lt;LANG&gt;_FLAGS"><code class="xref cmake cmake-variable docutils literal notranslate"><span class="pre">CMAKE_&lt;LANG&gt;_FLAGS</span></code></a> variable in the test project so that the
test compilation works as it would in the main project.  However, CMake 3.6 and
below do not also honor config-specific compiler flags such as those in the
<span class="target" id="index-0-variable:CMAKE_&lt;LANG&gt;_FLAGS_DEBUG"></span><a class="reference internal" href="../variable/CMAKE_LANG_FLAGS_DEBUG.html#variable:CMAKE_&lt;LANG&gt;_FLAGS_DEBUG" title="CMAKE_&lt;LANG&gt;_FLAGS_DEBUG"><code class="xref cmake cmake-variable docutils literal notranslate"><span class="pre">CMAKE_&lt;LANG&gt;_FLAGS_DEBUG</span></code></a> variable.  CMake 3.7 and above prefer to
honor config-specific compiler flags too.  This policy provides compatibility
for projects that do not expect config-specific compiler flags to be used.</p>
<p>The <code class="docutils literal notranslate"><span class="pre">OLD</span></code> behavior of this policy is to ignore config-specific flag
variables like <span class="target" id="index-1-variable:CMAKE_&lt;LANG&gt;_FLAGS_DEBUG"></span><a class="reference internal" href="../variable/CMAKE_LANG_FLAGS_DEBUG.html#variable:CMAKE_&lt;LANG&gt;_FLAGS_DEBUG" title="CMAKE_&lt;LANG&gt;_FLAGS_DEBUG"><code class="xref cmake cmake-variable docutils literal notranslate"><span class="pre">CMAKE_&lt;LANG&gt;_FLAGS_DEBUG</span></code></a> and only use CMake’s
built-in defaults for the current compiler and platform.</p>
<p>The <code class="docutils literal notranslate"><span class="pre">NEW</span></code> behavior of this policy is to honor config-specific flag
variabldes like <span class="target" id="index-2-variable:CMAKE_&lt;LANG&gt;_FLAGS_DEBUG"></span><a class="reference internal" href="../variable/CMAKE_LANG_FLAGS_DEBUG.html#variable:CMAKE_&lt;LANG&gt;_FLAGS_DEBUG" title="CMAKE_&lt;LANG&gt;_FLAGS_DEBUG"><code class="xref cmake cmake-variable docutils literal notranslate"><span class="pre">CMAKE_&lt;LANG&gt;_FLAGS_DEBUG</span></code></a>.</p>
<p>This policy was introduced in CMake version 3.7.  Unlike most policies,
CMake version 3.16.5 does <em>not</em> warn by default when this policy
is not set and simply uses <code class="docutils literal notranslate"><span class="pre">OLD</span></code> behavior.  See documentation of the
<span class="target" id="index-0-variable:CMAKE_POLICY_WARNING_CMP&lt;NNNN&gt;"></span><a class="reference internal" href="../variable/CMAKE_POLICY_WARNING_CMPNNNN.html#variable:CMAKE_POLICY_WARNING_CMP&lt;NNNN&gt;" title="CMAKE_POLICY_WARNING_CMP&lt;NNNN&gt;"><code class="xref cmake cmake-variable docutils literal notranslate"><span class="pre">CMAKE_POLICY_WARNING_CMP0066</span></code></a>
variable to control the warning.</p>
<div class="admonition note">
<p class="admonition-title">Note</p>
<p>The <code class="docutils literal notranslate"><span class="pre">OLD</span></code> behavior of a policy is
<span class="target" id="index-0-manual:cmake-policies(7)"></span><a class="reference internal" href="../manual/cmake-policies.7.html#manual:cmake-policies(7)" title="cmake-policies(7)"><code class="xref cmake cmake-manual docutils literal notranslate"><span class="pre">deprecated</span> <span class="pre">by</span> <span class="pre">definition</span></code></a>
and may be removed in a future version of CMake.</p>
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